JP2015154047A5 - - Google Patents

Claims (8)

A method of selectively etching a first region made of silicon oxide with respect to a second region made of silicon nitride,
The object to be processed having the first region and the second region is represented by CxFy so that the thickness of the protective film on the second region is larger than the thickness of the protective film formed on the first region. A protective film forming step of forming a protective film by exposing to a fluorocarbon gas plasma ;
A first region etching step of etching the first region by exposing the object to be processed to a fluorocarbon gas plasma;
Including
The high frequency bias power supplied to the mounting table for mounting the object to be processed in the protective film forming step is smaller than the high frequency bias power supplied to the mounting table in the first region etching step ,
In the protective film forming step , the temperature of the object to be processed is set to a temperature of 60 ° C. or more and 250 ° C. or less.
Method. Hydrogen, nitrogen, and by generating a plasma of a gas containing fluorine, and affected region formation step of Ru denature said first region configured to affected region made up of ammonium fluorosilicate from the silicon oxide,
An altered region removing step of removing the altered region ;
Further including
The second region is embedded in the first region;
2. The method according to claim 1, wherein the protective film forming step and the first region etching step are performed after the second region is exposed by the altered region forming step and the altered region removing step . The method according to claim 2, wherein the object to be processed is heated in the altered region removing step . The method according to claim 2, wherein in the altered region removing step , the object to be processed is exposed to an inert gas plasma. The method according to any one of claims 2 to 4, wherein the altered region forming step and the altered region removing step are alternately performed a plurality of times. In the protective film formation step, as the fluorocarbon _{gas, C 4 F 6, C 4} F 8, and a gas containing at least one of _C 6 _{F 6} is used, in any one of claims 1 to 5 The method described. The method according to claim 1, wherein the protective film forming step and the first region etching step are alternately performed . In the protective film formation step, the high-frequency bias power is not supplied to the mounting table in which the workpiece is placed thereon, the method according to any one of claims 1 to 7.